Electric wall heater



Dec. 20, 1932. R, GRIERSON ELECTRIC WALL HEATER Filed Feb. 7. 1930 Patented Dec. 20, 1932 UNITED sTATEs RONALD GRIERSON, F LONDON, ENGLAND ELECTRIC WALL HEATER Application led February 7, 1930; Serial No. 426,651, and in Great Britain February 25, 1929.

This invention refers to the method of constructing and to the system of installing electrical conductors for use in obtaining radiant heat for warming rooms or buildings,

and for other purposes where it is desired to obtain radiant heat, the object being to produce electrical conductors built up into secftions or lengths or panels ready for erection in which all heat or practically all heat is thrown forward and not allowed to pass backwards so that practically the whole of the heat generated is radiated from the surface of the wall, floor or ceiling of the room or building.

According to this invention I employ a slab, preferably cork, or other suitable material having an area-say approximately twelve superficial square feet, and 1 inch thick to constitute a heat insulating medium behind the insulated conductors, and in order to add rto the rigidity of the slab during the process of building up the panel, to facilitate the fixing of same, to prevent sagging after fixing, and to insert a non-ignitable partition or slab between the cork and the structure, we secure such cork slab to a cement-asbestos board or equivalent of suitable thickness.

When however I use a material which is suliciently rigid or otherwise suitable for my purpose I may dispense with the cementasbestos slab.

Having secured the cork slab to the cement asbestos board I then place the insulated Wire in position, keeping it preferably about i one eighth of an inch clear of the surface of the cork. This I accomplish by the use of what I term formers, consisting of two L-shaped metal strips each carrying a movable and adjustable bar provided with a number of studs or pegs, the L shape strips being fixed the required distance apart to the Workship bench. The cork-faced board is placed between the L strips and when the studded bars have been suitably adjusted the 4" insulated Wire is wound on rthe pegs thus keeping it clear ofthe surface of the cork. After the wire is Wound plaster of Paris or other suitable `material is poured over the wires on to the cork until the surface of the plaster 5 is just about level with the upper surface of the wires. Immediately the plaster sets, the tension of the wires is released by loosening the adjustable bars, fthe Whole element being then removed from the formers, the result being a cork-faced board or panel carrying a thin layer of plaster' of Paris in which the insulated wire is firmly embedded.

In order that the invention may be clearlyv understood I have appended the accompanying drawing.

Fig. 1 is a plan view of the former or frame showing the insulated wire wound thereon with the cork slab in position ready to receive the plaster of Paris in which fthe wires are embedded.

Fig. 2 is an elevation of Fig. 1.

Fig. 3 is a sectional view of a portion of a built-up panel with the rendering and finishing coat of plaster from the surface of which the heat radiates.

In building up the panel or unit ready for erection I take a slab lA, preferably cork which I may render more rigid by securing it to a cement-asbestos board a1. The conductor wires a2 are now arranged in posi' tion, say about one eighth of an inch clear of the surface of the cork slab, and in order to accomplish this I employ what I term a former, consisting of two L-shape strips B, each carrying a movable and adjustable bar b1 provided with a plurality of pegs b2.

The strips B are first fixed to the workshop bench the required distance apart, then the slab A is placed between these strips B, being maintained in position by thewood packing pieces b3, and after the bars b1 have been adjusted by the tightening screws b* so that the edges of said bars b1 rest upon the edges of said slab A in which position they are held by the distance pieces b5, the wire a2 is wound on the pegs b2, thus keeping it clear of the surface of the slab A, as clearly shown by ilaster of Paris a3 or other material is now poured over the wires a2 onV to the slab A 95 until the surface of the plaster is just about level with the upper surface of the wires a2, then when the plaster a3 is set the tension of the wires is released by loosening the tightening screws b4 and freeing the bars b1, the 100 result being a panel comprising a board a1 faced withr av cork slab A carrying conductor wires a embedded in a thin layer of plaster a. Or I may constitute the bars b1 so 5 that the gs b project through holes provided in t e slab ,i thus enabling the coating olf laAster as to cover the whole surface of the s a These panels orl units are laced in position in or on the ceiling or ot er part either side by side or end to'end, or other convenient manner, and to facilitate connections between the panels or units and between the circuit wir and the panel wires a, I provide small boxes a* which are countersunk into the surface of the cork face, in which the connections are made in the usual'manner or the boxes a may be otherwise arranged, the whole being then covered with the finishing plaster a:s or e uivalent, as 'clearly shown by Fig. 3, from t e surface of which plaster a5 the heat radiates. Or the finishing plaster a may be laid on each panel when buildingup the unit in the workshop. What I claim as my invention and desire to secure by Letters Patent is An electrically heatedwall board comprising a slab of heat insulating material, a reinforcing backing member for said slab, electrical resistance' Wiring ks aced from said slab, and a monolithic sla formed on said insulating slab vand embedding said resistance wiring therein, said resistance wiring being tensioned and securely held in a predetermined arrangement before being embedded to form convolutions extending throughout the entire area of said monolithic slab, and a slab of finishing material over said monolithic slab.

In testimony whereof I have aixed my signature.

- RONALD GRIERSON. 

